chore: fix static analysis

Author: dpanta94

src/Admin/Provider.php

@@ -275,15 +275,15 @@ public function hijack_current_parent_file( $submenu_file ) {
 		}
 
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
-		$current_page = isset( $_GET['page'] ) ? sanitize_text_field( wp_unslash( $_GET['page'] ) ) : '';
+		$current_page = isset( $_GET['page'] ) ? sanitize_text_field( (string) wp_unslash( $_GET['page'] ) ) : '';
 
 		if ( $current_page !== self::get_single_page_slug() ) {
 			return $submenu_file;
 		}
 
 		global $plugin_page;
 
-		self::$stored_parent_file = $plugin_page;
+		self::$stored_parent_file = is_string( $plugin_page ) ? $plugin_page : null;
 
 		$plugin_page = self::$parent_page; // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited
 

src/views/single.php

@@ -26,11 +26,12 @@
 $description     = $migration->get_description();
 $rest_base_url ??= '';
 $executions    ??= [];
+$list_url      ??= null;
 
 $template = Config::get_template_engine();
 ?>
 <div class="wrap stellarwp-migration-single" data-rest-url="<?php echo esc_url( $rest_base_url ); ?>" data-migration-id="<?php echo esc_attr( $migration_id ); ?>">
-	<?php if ( $list_url ) : ?>
+	<?php if ( is_string( $list_url ) ) : ?>
 		<div class="stellarwp-migration-single__back">
 			<a href="<?php echo esc_url( $list_url ); ?>" class="stellarwp-migration-single__back-link">
 				<span class="dashicons dashicons-arrow-left-alt2"></span> <?php esc_html_e( 'Migrations', 'stellarwp-migrations' ); ?>